Reverse 200

I can get some odd text file. After some investigation (by googling “ASK/Manchester Clock 64″), I realize that this is output of RFID tag’s bit stream.

How can I get tag number? Accoding to this site http://ift.tt/2t9Qcuq, Output bitstream is repeated tag information by dividing “111111111”, so I extract tag information (part of green letters in below) and calculate it.

The flag is: You must be at least this tall to play DEF CON CTF 5b43e02608d66dca6144aaec956ec68d

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magic

This challenge is similar to crackme challenge, but I need to solve and find flag from many binaries (200 files).

So I try to automate solve method by using python+capstone.

At first I try to find out where this binary start the subroutine which compare user input. After several minutes, I find out all of binary’s subroutines may be in the range from 0x000000000000093B to 0x0000000000000dff (it don’t need to adjust accurately, because all I need is to be able to pick up all of “cmp rdi, XXh”)